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I have a 75 gallon with 30 gallon sump. AI Hydra 26 lights. Last summer my LED lights starting doing weird things like certain lights in the pucks wouldn't come on or they would flicker. I didn't pay too much attention because I was so busy. By the time I realized I had a problem and called Aqua Illumination for help, I was in bad shape. The rep said I had to send them in to let them look at the lights so I spent $100 to overnight them. It was a hardware problem and I'd only had them a couple years. I had to buy new ones "at a discount". I didn't have a spare light so put a large plant growing light fixture over the tank for about 5 days while I waited for my new lights on the slow boat. Some corals have recovered but I lost all of my SPS, some really large colonies. Now my show piece coral, a super large wall neon green hammer that my clown hosts in is slowly shrinking. It used to take up about a quarter of my tank. I've been trying to adjust the lights up then down. I've tried target feeding it. Everyone seems to have a different idea online of where these lights should be. I haven't found anything that the hammer likes. My other hammers are also shrinking. Some corals seem to be just fine and thriving. Also the sand has a weird texture like reddish hard layer over the top. My temp is usually around 78.5-79. Salinity is 1.027. Calcium is 410. I have a PH monitor but battery is dead. Anyone have thoughts on what I can try to save the rest of my corals? I do not have a light meter and would honestly rather not buy one. I have so much money in this thing as it is. I'm attaching some photos. One is hammer a couple months ago to compare. Thanks for any help. Tank has been running about 8-9 years.
I tried posting on another reef site but no-one responded. Hoping someone will at least chime in here. Thanks!

definitely a huge help for answers would be test parameters for your water.
calcium alk mag (I did just notice you listed calcium and specific gravity but more info would be really helpful)
Changing lights can be really hard on corals especially with the intensity of LED it can take a up a few weeks for corals to acclimate find a position for them and leave them there if you keep changing the location intensity the corals have to burn energy trying to adjust to the different lighting conditions.

yes... post more parameters.. alk/nitrates/phosphates,etc...
and give an indication of how stable you have kept them.. corals enjoy stability over anything..
tell us your lighting schedule (how long..what percentages,etc...)
what is your water change schedule? how much..how often..
feeding?
etc...?

photo 4 seems to show most of your corals look pretty bleached.. is that just the photo or are they?

The simple answer is that they will not do it alone. I do think that hard corals under most LEDs are less hardy and need everything to be more perfect with less margin for error to thrive, but none of this is impossible. Most softies do not really seem to care about lights.

For the quick guide, make sure that the whites are fairly low - the waves that they give off have some harsh peaks that can harm coral that are not healthy enough to fight it off. This is not a "too much" thing (intensity), but a "wrong kind" thing. I would keep these under 20%.

If you are really unsure of the LED, just go and get a cheap hydroponics 4 bulb T4 and put some cheap GE 6500K bulbs in it. If the coral perks up, then get bluer bulbs and make a better unit. 6500K is a great spectrum for coral.

How do I add more photos. I meant to add a screenshot of my lighting schedule.
I typically do a 5 gallon water change every weekend.
I will reduce the whites and see what happens.
Also will post more parameters once I get a chance.
Thank you all for your comments.

I didn't have a spare light so put a large plant growing light fixture over the tank for about 5 days while I waited for my new lights on the slow boat..... Also the sand has a weird texture like reddish hard layer over the top.

Sounds like the grow light fueled a bacterial or cyano outbreak. It would have been better to lights out for 5 days, than place a grow light (just my opinion.)

I would lights out for minimum 3 days, and slowly ramp them up over 2 weeks. Give your corals a chance to recover and allow your water column to resolve your bacterial issues.

I honestly don't if these tests are correct. I will try testing again this weekend to see if it comes out the same. Seems high for nitrates. I do regular water changes. Have clean low tds rodi water. Only 2 fish. No overfeeding now that I don't have any anthias. Macro algae in my 30 gallon sump. Decent clean up crew.

2 no3 and .02 is not high, in fact jts a pretry decent level to maintain could even come up just a hair. I would say yes the extended lackmof light then blasting then with light then changing lights did had an effect on the corals. Dim the lights way down and given them a month then slowly increase the lighting every week.

Can anyone help here? I don't want to have to replace the expensive LEDs that I bought but my tank was overflowing with corals and now they are gasping their last breaths. I know I can't save them on my own. I'll give this forum one last try and then I guess it's RIP to my underwater garden. It's hard to watch them die like this and not know what to do to save them. Seems like everyone has a different idea of what the lights should be. I went away for a week and left the lights as is, so it's not the changing of the lights, for sure. Are whites too high? Blues? What? Ugh! I'm at my wits end and so sad.

Got to home depot and get a pair of T5 strip lights and a 4x GE 6500K bulbs. See if these arrest your fall and help a bit. These are great spectrum for coral, but bad to look at anymore where people want a bluer tank. If so, then ditch your LEDs and get a nicer T5 setup.

Most lps can handle no light for 5 days, the problem comes when u hit them with to much light at once after lights out. I don’t think the grow light is strong enough to help the coral & probably only helped out the algea. I agree with desertreef, I would turn the lights way down & slowly ramp them up ever 5 to 7 days.

It isn’t the lights themselves causing your issues which I’m sure u know being u have had success with the same lights for a few years. I think they just got hit with to much light after being under the weak grow light. A lot of lps & euphylia in perticular can handle quite a bit of light, but they have to be acclimated properly

I would keep an eye out that it is not the clowns irritating the hammer. Hammers weren't really meant for hosts, and ive heard on forums here before of clowns being too rough with euphyllia corals and making them not open up much any more.

I do not dose and never have. I had hard corals growing up and out of my tank over the years without a problem. I just think it's the lighting. Maybe I'm wrong. Only thing I do is a 5 gallon water change once a week and 1/8 tsp of calcium per day. I have cut back a little on that since my corals has disappeared and the need is not so great.

I think itís very unlikely for lights to kill corals rapidly. Corals can survive with no lights for 5 days and even if you blast them with bright lights after that they may be unhappy and the may start to bleach, but itís unlikely that they would flat out die like you describe. I suspect that there may be more going on here than just the lights.

Especially if the lights were replaced with the same lights and you had them at the same settings as the old ones then there shouldnít really be a problem there.

I would test your water parameters and do so quickly. Check for ammonia as that can definitely kill things quickly and check the pH and alkalinity check the salinity. If youíre using a cheap hydrometer, maybe get a refractometer to make sure itís really where you think it is. Go out and buy test kits if you need to. If youíve done water changes make sure that no chlorine or chloramines in the new water.

As far as the lights go, just set them to a low to medium value and run them 8 hours a day. Setting the lights to 60% instead of 50% or 40% instead of 45% isnít going to rapidly kill corals. I really think that there is something else going on here. Once you figure out whatís happening and why your corals are dying then you can work on fine tuning the lights.

Got to home depot and get a pair of T5 strip lights and a 4x GE 6500K bulbs. See if these arrest your fall and help a bit. These are great spectrum for coral, but bad to look at anymore where people want a bluer tank. If so, then ditch your LEDs and get a nicer T5 setup.

Have you tried uploading one of the tried and true lighting schedules that are readily available and then setting an acclimation since you now have a new (presumably fully functioning) fixture???

I have been searching but everyone has a different idea. The AI site has some crazy photos of the lighting schedule which I don't want to try. I have tried multiple different lighting ideas from people, some saying red and green need to be very low, some saying white needs to be super low, some saying UV can burn your corals. It's very confusing. After lowering my lights as suggested in the previous posts and being gone from home a couple of days, my green hammer is worse. Maybe I need to try the cheap lighting like suggested to see if that works.

I think itís very unlikely for lights to kill corals rapidly. Corals can survive with no lights for 5 days and even if you blast them with bright lights after that they may be unhappy and the may start to bleach, but itís unlikely that they would flat out die like you describe. I suspect that there may be more going on here than just the lights.

Especially if the lights were replaced with the same lights and you had them at the same settings as the old ones then there shouldnít really be a problem there.

I would test your water parameters and do so quickly. Check for ammonia as that can definitely kill things quickly and check the pH and alkalinity check the salinity. If youíre using a cheap hydrometer, maybe get a refractometer to make sure itís really where you think it is. Go out and buy test kits if you need to. If youíve done water changes make sure that no chlorine or chloramines in the new water.

As far as the lights go, just set them to a low to medium value and run them 8 hours a day. Setting the lights to 60% instead of 50% or 40% instead of 45% isnít going to rapidly kill corals. I really think that there is something else going on here. Once you figure out whatís happening and why your corals are dying then you can work on fine tuning the lights.

I can't imagine I would have ammonia in my water since I have RO DI and check tds pretty regularly. Had my whole system redone last summer at a cost of about $500. Also, we are on well water so don't think I'd have chlorine either. We change out a whole house filter and iron filter regularly.

I have a refractometer that I use with regularity.

My corals are not bleaching, just shrinking. The soft corals don't seem to be bothered in the least.